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We propose a scheme for implementing quantum gates and entanglement between spin qubits in the outer dots of a triple-dot system with an empty central dot. The voltage applied to the central dot can be tuned to realize the gate. Our scheme…

Quantum Physics · Physics 2015-03-19 Jose Garcia Coello , Sougato Bose

We present Coulomb Blockade measurements of two few-electron quantum dots in series which are configured such that the electrochemical potential of one of the two dots is aligned with spin-selective leads. The charge transfer through the…

Mesoscale and Nanoscale Physics · Physics 2016-08-16 M. Ciorga , M. Pioro-Ladrière , P. Zawadzki , J. Lapointe , Z. Wasilewski , A. S. Sachrajda

We present transport measurements on a lateral double dot produced by combining local anodic oxidation and electron beam lithography. We investigate the tunability of our device and demonstrate, that we can switch between capacitive and…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 M. C. Rogge , C. Fuhner , U. F. Keyser , R. J. Haug

We study the nonequilibrium spin transport through a quantum dot containing two spin levels coupled to the magnetic electrodes. A formula for the spin-dependent current is obtained and is applied to discuss the linear conductance and…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Ping Zhang , Qi-Kun Xue , Yu-Peng Wang , X. C. Xie

Spin-orbit coupling is key to all-electrical control of quantum-dot spin qubits, and is frequently stronger for holes than for electrons. Here we investigate Pauli spin blockade for two heavy holes in a gated double quantum dot in an…

Mesoscale and Nanoscale Physics · Physics 2017-05-31 Jo-Tzu Hung , Elizabeth Marcellina , Bin Wang , Alexander R. Hamilton , Dimitrie Culcer

Double quantum dot systems in the spin blockade regime exhibit leakage currents that have been attributed to the Hyperfine interaction. We model weakly coupled double-dot transport using a rate equation approach which accounts for Hyperfine…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 J. Inarrea , C. Lopez-Monis , A. H. MacDonald , G. Platero

We study the two-qubit controlled-not gate operating on qubits encoded in the spin state of a pair of electrons in a double quantum dot. We assume that the electrons can tunnel between the two quantum dots encoding a single qubit, while…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Dimitrije Stepanenko , Guido Burkard

Recent achievements in the field of gate defined semiconductor quantum dots reinforce the concept of a spin-based quantum computer consisting of nodes of locally connected qubits which communicate with each other via superconducting circuit…

Mesoscale and Nanoscale Physics · Physics 2020-05-28 Jorge Cayao , Mónica Benito , Guido Burkard

We investigate spin currents and spin-current correlations for double quantum dots in the spin blockade regime. By analysing the time evolution of the density matrix, we obtain the spin resolved currents and derive from a generating…

Mesoscale and Nanoscale Physics · Physics 2008-11-21 Rafael Sánchez , Sigmund Kohler , Gloria Platero

In terms of the exact quantum master equation solution for open electronic systems, the coherent dynamics of two charge states described by two parallel quantum dots with one fully polarized electron on either dot is investigated in the…

Mesoscale and Nanoscale Physics · Physics 2013-08-20 Jinshuang Jin , Wei-Min Zhang , Matisse Wei-Yuan Tu , Nien-En Wang

We study the spin-dependent transport properties of a spin valve based on a double quantum dot. Each quantum dot is assumed to be strongly coupled to its own ferromagnetic lead, while the coupling between the dots is relatively weak. The…

Mesoscale and Nanoscale Physics · Physics 2021-07-21 Patrycja Tulewicz , Kacper Wrzesniewski , Szabolcs Csonka , Ireneusz Weymann

We investigate coherent time-evolution of charge states (pseudo-spin qubit) in a semiconductor double quantum dot. This fully-tunable qubit is manipulated with a high-speed voltage pulse that controls the energy and decoherence of the…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Toshiaki Hayashi , Toshimasa Fujisawa , Hai-Du Cheong , Yoon-Ha Jeong , Yoshiro Hirayama

Silicon quantum dot spin qubits provide a promising platform for large-scale quantum computation because of their compatibility with conventional CMOS manufacturing and the long coherence times accessible using $^{28}$Si enriched material.…

Electronic transport through a triple-quantum-dot ring with three terminals is theoretically studied. By introducing local Rashba spin-orbit interaction on an individual quantum dot, we find that the spin bias in one terminal drives…

Mesoscale and Nanoscale Physics · Physics 2010-08-17 Weijiang Gong , Hui Li , Guozhu Wei

A crucial requirement for quantum information processing is the realization of multiple-qubit quantum gates. Here, we demonstrate an electron spin based all-electrical two-qubit gate consisting of single spin rotations and inter-dot spin…

Quantum Physics · Physics 2015-05-30 R. Brunner , Y. -S. Shin , T. Obata , M. Pioro-Ladrière , T. Kubo , K. Yoshida , T. Taniyama , Y. Tokura , S. Tarucha

Electronic transport through a two-path triple-quantum-dot system with two source leads and one drain is studied. By separating the conductance of the two double dot paths, we are able to observe double dot and triple dot physics in…

Mesoscale and Nanoscale Physics · Physics 2016-08-03 M. Kotzian , F. Gallego-Marcos , G. Platero , R. J. Haug

We study the coupling between a singlet-triplet qubit realized in a double quantum dot to a topological qubit realized by spatially well-separated Majorana bound states. We demonstrate that the singlet-triplet qubit can be leveraged for…

Mesoscale and Nanoscale Physics · Physics 2019-04-24 Marko J. Rančić , Silas Hoffman , Constantin Schrade , Jelena Klinovaja , Daniel Loss

For a double quantum dot system in a parallel geometry, we demonstrate that by combining the effects of a flux and driving an electrical current through the structure, the spin correlations between electrons localized in the dots can be…

Strongly Correlated Electrons · Physics 2015-06-15 C. A. Büsser , F. Heidrich-Meisner

Solid state quantum bits are a promising candidate for the realization of a scalable quantum computer, however, they are usually strongly limited by decoherence. We consider a double quantum dot charge qubit, whose basis states are defined…

Mesoscale and Nanoscale Physics · Physics 2015-06-24 Udo Hartmann , Frank K. Wilhelm

A scalable optical quantum information processor is likely to be a waveguide circuit with integrated sources, detectors, and either deterministic quantum-logic or quantum memory elements. With microsecond coherence times, ultrafast coherent…